In a cutting insert for grooving process, a lower feed rate of the cutting insert tends to reduce the thickness of chips obtained. Thin chips have low rigidity, and hence it may be difficult for the chips to be stably discharged outside.
On the other hand, for example, patent document 1 discloses a cutting insert in which in a rake surface formed continuously with a cutting edge, a region of the rake surface corresponding to a middle part of the cutting edge is inclined downward, and regions of the rake surface corresponding to both end parts of the cutting edge are inclined upward. The chips generated by the cutting insert are deformed in a wave shape depending on the angle of the rake surface, thus enhancing rigidity of the chips.